1. Field of the Invention
Example embodiments of the present invention relate to a semiconductor device and a method of manufacturing the semiconductor device. More particularly, example embodiments of the present invention relate to a semiconductor device having an improved structure of gate edges and a method of manufacturing the semiconductor device.
2. Description of the Related Art
Generally, a semiconductor device, e.g., a switching element, may be formed on a semiconductor substrate by a series of processes. For example, a layer may be formed on a semiconductor substrate, and a photolithography process may be used to form an etching mask, e.g., photoresist patterns, on the layer. Then, the layer may be etched, e.g., an anisotropic etching process or an isotropic etching process, through the etching mask, so the layer or portions of the substrate may be transformed into patterns having specific characteristics.
A conventional photolithography process may include an exposure process, e.g., use of optical equipment for transcribing predetermined image patterns on a photoresist layer. The resolution and depth of focus when forming the predetermined image patterns may depend on a wavelength of light and a diameter of a projection lens in the optical equipment. In particular, as unit cell areas become smaller and integration degree of semiconductor devices increases, sizes of the predetermined image patterns formed by the photolithography process may decrease, i.e., very fine patterns.
Use of the conventional photolithography process to form very fine patterns, however, may cause inconsistent edge sizes. In particular, edge portions of fine patterns formed via the photolithography process may be formed to be smaller than their corresponding theoretical values due to light interference or a difference in an etching amount. When inconsistent edge sizes of a mask are sued to form a gate, edges of the gate may be smaller than an expected size, thereby increasing leakage current. As a result, resistance to a punch-through phenomenon due to hot carrier electrons may be reduced in the semiconductor device.